Block-signal system.



P. B. CDREY. BLOCK SIGNAL SYSTEM. APPLICATION FILED MAR.30, 190aPatented Jgn.12,1909.

I I 1 I T FRED B. CURE/Y. BY Q2 amasm. f

UNITED sTArEs PATENT OFF/ICE.

FRED B. COREY, OF SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRICCOMPANY, A CORPORATION OF NEW YORK.

BLOCK-SIGNAL SYSTEM.

Specification of Letters Patent.

Patented Jan. 12, 1909.

Application filed March 30, 1908. Serial No. 42%,036.

that is, systems in which the signal arms are arran ed to'assume threedistinct positions to indicate danger caution and clear, respectively.In such a system it is customary to,employ contacts on each signal tocontrol the movement of the signal next in the rear from caution toclear position. This control is ordinarily performed through ,a linerelay, sometimes termed a three position relay, placed at the signal inthe rear. It has furthermore been customary to construct three positionsignals with a stationary lock magnet, or some similar device, so thatthe signal maybe stopped in caution position, When it is moved fromclear position by a train backing into the block in advance and therebyputting the signal for the a block in advance from caution to dangerpbsition. With some signal mechanyisms, however, as for instance such asignal 'mechanism as is described i Patent #868,648 issued October 22nd,19o /,1t is not possible, conveniently, to provide means. for stoppingthe signal in an mtermediate position when moving from clear towarddanger; It therefore becomes necessary when the signal is to move fromclear to caution, to allow it to move first to danger positionmomentarily and then to return to caution. In a signal operating in 40this manner, however, it has not heretofore been practicable any longerto control the signal in the rear from contacts on the signal shaft,since if a train should back into one block putting the si al at danger,it

would throw the signa for the block next in the rear, from clear tocaution, but in making this movement the signal for thc block 111 therear, having to move momentarily t0 dan er position, would throw thenext signal be ind it from clear position momentarily to dan er, andthis action I might be repeated for t e entire length of the road. Forthis reason, when signals of the type described in my former patent havebeen operated as three position signals,- it

has been customary to control the movement of each signal from cautionto clear and vice versa, not by contacts on the shaft of the si nal inadvance, but by contacts on the trac relay for the block in advance.This, however, is objectionable, because, if a block is clear butthesignal mechanism out of order, the signal for that block might standat danger with the signal next in the rear at clear. That is, eachsignal no longer under all conditions accurately indicates the conditionof the signal in advance and the failure of a signal mechanism mayresult in forcing each train approaching it to "make an emergency stopin order to avoid running past it. .1

By means of my invention 1 am enabled to control each signal by contactson the signal mechanism itself of the block next in ad- .vance and yettoavoidj throwing a series of signals to dangers behind a train when itbacks into a blocks I accomplish this by pro- 'viding means fo'rr'endering the contacts on the signal shaft inoperative to control thesignal next in the reanwhen the first mentioned signal goes momentarilyto danger inmoving from "clear to. caution. More specifical y stated, Iprovidemeans for shortcircuiting the contacts when the driving motor ofthe, signal is in operation.

My inventionwill'best be understood by reference to the;drawing whichshows diagrammatically ai signal! system arranged in accordance with inyinvention.

. In the drawing, A, A and A represent the rails of three successiveblocks supplied With current from track batteries B, B and B The block Ais shown occupied by a train and the direction of traffic is indicatedby an arrow.

(1,"(1 and C re resent track relays for three blocks, the re ay O beingdenergized, and the other two being energized since their blocks areclear.

D, D and D represent the signals for the block's. These are threeposition signals, the signal D being shown atdanger posi tion, thesignal D at caution and the signal D at clear; The signal mechanisms areshown dia rammatically; their construction may be i( entical with thatdescribed in my former patent No. 868,648 above re-. ferred to. r

E represents the driving motor for the signal D. This motor is providedwith a with an auxiliary series winding G represents the line or threeposition relay which controls the movement of the signal from caution"to'clear.

H represents the switch contacts which move with the signal arm. Thesecontacts would, in practice, be placed on the signal shaft, and would beconstructed substantially as shown in my prior patent, but for the sakeof clearness in illustration 1 have shown the contacts developed on aplain surface. There are nine stationary contacts h to 71. and. movablecontacts as shown.

T represents the battery, or the source of current for supplyin thesignal mechanism.

J represents a re ay connected in series with the motor and arranged toshort-circuit the pair of contacts h and k The operation of the systemis as follows: As long the car or train remains in block A, the signalswill remain in the position shown. Wlien the train passes out block A,track relay C is energized and closes the circuit from the left handterminal of the battery through relay J, series clutch magnet Winding f,motor field 6, motor armature E, contacts 7r, h and h and armature oftrack relay C, to right'hand terminal of battery I. The circuit of theshunt winding]? of the clutch or slot magnet is closed through contactsh it and k and the contact of track relay C. Both motor and slot magnetare consequently energized and the motor begins to drive the signal fromdanger-position. When the caution iosition is reached the circuitconnections become the same as are shown for signal D The circuit of themotor is open at contact in so that the signal arm comes to rest, thecircuit of the shunt winding of the slot magnet bcing kept closed. Whilesignal D has thus been moving from danger to caution position, signal Dhas been moving from caution to clear position, because since thecircuit of the motor E is closed, re-,

lay J in series with it is energized, thereby.

closing a circuit from the left hand terminal of battery I through thearmature of relay ,J, through the upper line wire to line relay G backthrough the lower line wire and through armature of track. relay 0 toright hand terminal of battery I. Line relay G is conseuently energizedand closes the circuit from t e left hand terminal of battery I throughrelay J slot magnet f series field e, armature E contacts h h armatureof relay G, and armature of relay C to the right hand terminal ofbattery I Signal D is therefore driven from caution to clear. osition.When clear position is reache the circuit connections become the same asthose shown in signal D The motor is 'disconnected from the battery atcontact 7L3 butis short-circuited through contacts 71 and h,

and therefore, because of its shunt field, acts relay G is notdeenergize. when the signal D reaches caution position and the circuitof motor E 18 opened because before this time the circuit of line relayGr has been closed by the contacts ]i and k of switch H.

So far as the movement of the signalsfrom danger to caution and to clearis concerned, the relay J performs no useful function except to causethe signal D to start its movement from caution to clear simultaneouslywith the movement of the signal D from danger, to caution. It is uponthe reverse movement of the signals that the operation of the relay Jbecomes of im ortance.

Suppose t at the train, after leaving" block A backs into this blockagain, thereby returning signal D to danger position; this opens thecircuit of line relay G andallows signal 1), which had been cleared, tostart back again toward danger position. Since the signal'mechanism isnot constructed so as to catch the signal arm at "caution position, itsmovement must be continued until danger position is reached; the

motor then immediately returning the arm to caution position. If it werenot for the relay the signal 1) would be thrown momentai'ily to dangerby the movement of si nal D to dan er and similaril the h n I signal inthe rear of D and all the remaining signals on the road might be thrown'to- Relay J}, however, prevents daiigei. this from occurring, for,before contacts h and /i have been opened by their movable contacts, thecircuit of motor E and conse' quentlv relay J 'lias been closed atcontacts h it and k The relay J is therefore energized and pulls up itsarmature to short-circuit contacts 7t and-7i before their circuit is vopened at their movable contacts.

Thus

the contacts h 70 of switch H are rendered inoperative to vopen thecircuit of line relay G when signal 1) goes only momentarily to dangerand motor E is in operation to drive it back to caution.

I do not desire to limit myself to the particular construction andarrangementgof 130' 1 at-ion.

- electric motor for moving said arm, contacts signal next in the reararranged to open said parts shown in the drawing, hut aim in theappended claims to cover all modifications I which are within the scopeof my invention. i What I claim as new and desire to secure l by LettersPatentof the United States, is, l 1. In a signal system, a signal armadapti ed to assume three distinct positions, a motor for moving saidarm, contacts controlled 1 by the movement olsaid arm controlling, the asignal next in the rear, and means for renderi ing said contactsinoperative to control the i signal in the rear when said motor is inoperl l l 2. In a signal system, a signal arm adapted to assumethreedistinct positions, a motor for moving said arm, contactscontrolled by the movement of said arm controlling the signal next inthe rear, and means for shortcircuiting' said contacts when said motoris in operation.

3. In a signal system, a sigma]. arm adapted to assume three distinctpositions, an electric motor for m'ovirnr said arm, contacts cgmtrolledhr the movement of said arm l controlling the signal next inthe'rcaryand 'a relay in circuit with said motor-adapted when energizedto render said contacjs inoperative to control the signal in. the rear.

4. Ina signal system, a signal arm adaptedto assume three distinctpositions, an

controlled by the movement of said arm controlling the signal next inthe rear, and a relay. in circuit with. said motor adapted whenenergized to short-circuit said contacts] 5. In a signal system, asignal arm adapt ed to assume three distinct positions to indicatedanger, caution, and clear, a motor for moving said arm, .a line relaycontrolling said arm in its clear position, contacts in circuit with'theline relay of the circuit when said arm is at danger and to close itwhen said arm is at caution or caution or clear clear when said armmoves clear,- and means for rendering said contacts inoperative to opensaid. circuit when said motor is in operation.

6. In a signal system, a signal arm adapted to assume three distinctpositions to ind cate danger, caution am clear, an electric motor formoving said arm, a line relay controlling said arm in its clearposition, contacts in circuit with the line relay of the signal next inthe rear arranged to open said circuit whensaid arm" is at danger and toclose it when said arm is at and a relay in circuit with said motorarranged when energized to short-circuit said contacts.

7. In a signal system, a signalarm adapted to assume three distinctpositions to md1 eate danger, ,cautioni'and clear, contacts controlledhythe movement of said arm and controlling the signal next in the rear tocause it to-move from caution to clear when said arm moves From danqer"to" caution, and'means for preventing said contacts from affecting thesignal in the rear when said arm goes momentarily todangerin moving fromclear to caution. 8; In a slgnalsystem, a signal arm adapted to assumethree distinct positions to lndlcate danger, caution and "clear",contacts controlled by the move'mentot said arm andcontrolhng the signalnext in the rear to cause it to move from caution to ger to caution, andmeans cuitlng' said contacts when said arm goes I P a momentarily todanger in movlng irom clear to caution.

In witness whereof, Ihave hereunto set my

